Sleep apnea is a disease in which apnea occurs during sleep without subjective symptom. It is more prevailing in male middle- and old-aged persons in their forties and fifties and approximately one per 100 persons is reported to suffer from the disease. In the disease there is repeated many times in sleep a sequence of 20-40 second's apnea, about 10 second's pneusis and 20-40 second's apnea. For example, approximately 400. occurrences of apnea during a 6.5-hour sleep, corresponding to a total apneic time of approximately 4 hours are observed. As a result, there occur phenomena such as daytime sleepiness to cause a trouble in driving or working, and when conditions are severer, loss of energy or appetite, swelling in the lower part of body and shortness of breath. Increase in leucocyte number, development of polycythemia and even cardiomegaly are then associated. Furthermore, decrease in oxygen concentration in blood is induced, which can be a cause of sudden death. The disease are observed not only in adults of middle or advanced age but also in infants, and may be an indirect cause of hypertension, cardiac insufficiency and arrhythmia.
Therapy currently adopted for the disease include bodyweight reduction (the frequency in obese people is as high as 83%), pressure application through the nose (CPAP), surgical operation (tonsillectomy or adenoidectomy) and use of a drug such as acetazolamide. Although drug administration is the simplest treatment among them, there have been found no effective drugs currently in use.